Submicron spatial resolution photoluminescence is used to assess radiative efficiency and spatial uniformity of GaN/InGaN heterojunctions. Room temperature photoluminescence of multiple InGaN quantum wells with GaN barriers fabricated by electron-cyclotron resonance assisted molecular beam epitaxy was measured as a function of position on a facet perpendicular to the layer structure. Our high resolution studies reveal that the radiative recombination for the InGaN quantum wells is 50–60 times more efficient than for the underlying GaN film. ©1997 American Institute of Physics.